Техника и технология пищевых производств (Dec 2015)
STUDY ON PROTEOLYSIS INTENSITY OF ENZYME SYSTEMS FORMED BY FUNGI OF GENUS OF PENICILLIUM AND RENNET
Abstract
Proteolysis is the main process among those occurring during cheese ripening. In cheese ripening process proteolysis takes place under the influence of specific enzymatic systems known as proteinases, milk-curdling enzymes and those synthesized by various microflora which is presented in cheese. Due to proteolytic reactions cheeses are enriched with an ammonia solution, the density of cheeses being reduced and their consistency being improved by becoming firmer. The catalytic activity of the enzyme systems of mold fungi Pеnicillium caseicolum has been studied . The research results revealed that acidic protease has the highest proteolytic activity, its value reaching 1.20 ± 0.07 uM (substrate) / mg (protein) ch. Acidic carboxypeptidase has the same catalytic activity as the alkaline aminopeptidase. The activity of these enzymes in the mycelium of mold fungi Pеnicillium caseicolum is 1.17 ± 0.07 uM (substrate) / mg (protein) ch, while metalloprotease has catalytic activity 1.14 ± 0.06 uM (substrate) / mg (protein) ch. The research results revealed that the combined use of mold fungi Pеnicillium caseicolum and rennet accelerates proteolytic processes when ripening of soft cheeses occurs. Electrophoretic analysis of cheese peptide profiles study demonstrates that mold fungi Pеnicillium caseicolum are the carriers of the proteolytic system of high activity. Thus, after 12 hours of protein substance hydrolysis their mass fraction lowed by 9-13%, and the mass fraction of free amino acids and peptides of different molecular weight increased. It has been established that the additional introduction of rennet into the sample accelerates the proteolytic processes. According to the presented peptide profiles the rate of accumulation of organic nitrogenous compounds increases.
